I paid 3K for an online coaching program. 2 months later I asked for half my money back because I was getting nothing out of it. No contract signed.

First, you will need proof of payment to have any chance for a refund. Next, depending on how long the course was, your desired refund of half back may or may not be reasonable. How was the course sold to you? By who? How. What promises were made? How did the course meet or fail to meet your expectations? Have you sent a written demand for refund (if not do this immediately)? Explain the reasons for your dissatisfaction. Give them a reasonable amount of time to respond. If they do not respond, you may well have to go to small claims court to be made whole. Depending on the character of the people who sold you the class, their reputaton ought to matter to them. Many vendors only respond when they get negative online reviews. Sorry I can't be more clear. Consulting an attorney couldn't hurt.   Good luck.